Cholera in Haiti: 800,000 cases?

By Jonathan Mayer, on March 15th, 2011

An article that is forthcoming in The Lancet concludes that there will have been a prevalence of nearly 800,000 cases of cholera in Haiti by the end of November, 2011–nearly double the number projected by WHO. WHO’s estimates have themselves been increasing dynamically and are not based on any knowledge of transmission dynamics–in short, they are educated guesses. The reference paper, posted online on March 16, 2011 (www.thelancet.com) is based upon a detailed knowledge of transmission dynamics and interventions, and is a recursive mathematical model by two well known disease modelers (Andrews JR and Basu S. Transmission dynamics and control of cholera in Haiti: an epidemic model. Lancet DOI:10.1016/S0140-6736(11)60273-0) Geographers and spatial epidemiologists will recognize that the model is a multiregional form of disease model that is based on the number of susceptible people, infected individuals, and recovered individuals (“SIR” models) that have been the basis for growth models for decades. Moreover, and perhaps *most importantly*, anticipated early declines in cholera incidence in the coming months are predicted to be part of the natural course of the epidemic, and not the result of any specific public health interventions.

Cholera is a waterborne bacterial disease, transmitted via the fecal-oral route, that can progress from asymptomatic stages to death within a period of less than 18-24 hours. The only effective treatment is oral or intravenous rehydration using physiologically balanced water/electrolyte solutions–with the electrolytes in clean water only. When available, this can be combined with oral or IV doxycycline, ciprofloxacin, or other appropriate antibiotics. Oral rehydration in this form–a fundamentally simple and low-tech treatment–was devised by Dr. Richard Cash of the Harvard School of Public Health, credited with saving millions of lives.